Cancer is one of the most tragic afflictions in modern society, and often results from alterations in the mitotic process. In normal cells, [unreadable]-catenin is found predominantly associated with the plasma membrane. However, in tumor cells, [unreadable]-catenin redistributes to the nucleus where it interacts with transcription factors to stimulate the expression of proteins that promote mitosis. The pathway is also important in CNS-related disorders ranging including manic depression, and Alzheimer's. In response to PAR-06-545 "Solicitation of Assays for High Throughput Screening (HTS) in the Molecular Libraries Screening Centers Network (R03)" we are submitting an assay to quantify the cellular distribution of [unreadable]-catenin. The assay involves exposing HeLa cells to test compounds that are likely to alter [unreadable]-catenin distribution; the cells are then immunostained for endogenous [unreadable]- catenin and photographed using high content robotic microscopy workstations. Specialized image analysis software is used to quantify cellular [unreadable]-catenin localization. In preliminary experiments, an inhibitor of glycogen synthase kinase 3-[unreadable] (GSK-3), an enzyme typically regulated by the Wnt-signal transduction pathway, induced nuclear localization of [unreadable]-catenin and this was quantified by the assay with a Z' score of 0.70. The proposed assay will help identify chemicals that are likely to regulate GSK-3 or other proteins that control [unreadable]-catenin localization. Discovery of such chemicals will contribute to our understanding of the regulation of [unreadable]-catenin localization and potentially help lead to development of novel therapeutics, depression, and dementia. [unreadable] [unreadable] [unreadable]